Based on a linkage and association mapping study of 1,031 multiplex autism families, rs10513025 was found to be associated with autism, and the expression of SEMA5A was seen to be reduced in brains from autistic patients. Although this finding was replicated, the authors caution that this SNP explains a very small fraction of the heritability of a complex disorder like autism, presumably due to their finding that the most common allele (present at a frequency of ~96%) is the allele associated with higher risk. The much rarer allele, rs10513025(C), is associated with a 0.55x reduced risk for autism (p=9.6x10e-6).10.1038/nature08490